Table 1.

PRC5-PTP co-purified proteins

Rank	MASCOT score	Expect value1	Accession number	Mr (Da)	Coverage (%)1	Annotation	Complex
1	20 000	∼0	Tb927.10.9660	87 636	76.6	SYF3	PRC
2	18 340	∼0	Tb927.5.1340	92 126	71.3	SYF1	PRC
3	7632	∼0	Tb927.9.11110	276 796	45.5	PRP8	U5
4	7134	∼0	Tb927.5.2290	249 282	38.8	BRR2 (U5-200K)	U5
5	6648	∼0	Tb927.2.3400	36 571	68.3	PRC3	PRC
6	4418	∼0	Tb927.9.10770	62 195	59.2	PABP2
7	3743	∼0	Tb927.8.1930	31 680	63.9	ISY1	PRC
8	3520	∼0	Tb11.v5.0469	49 672	38.5	Beta tubulin
9	3126	∼0	Tb927.1.2340	49 756	48.4	Alpha tubulin
10	2765	∼0	Tb927.10.7280	121 154	45.7	PRP22 * (DHX8)
11	2727	∼0	Tb927.2.5240	54 200	49.1	PRP19	PRP19
12	2727	∼0	Tb927.11.11610	64 578	45.5	Cactin
14	2342	∼0	Tb927.11.11330	76 002	49.9	HSP73
18	1938	1.1E–106	Tb927.11.2960	12 026	66.8	PRC5	PRC
19	1937	2.4E–122	Tb927.5.2060	80 135	48.7	CDC5	PRP19
22	1774	4.4E–112	Tb92711.10750	66 828	32.4	CWC22
23	1746	5.1E–109	Tb927.10.14360	36 525	44.0	U2A' (U2-40K)	U2
30	1615	3.5E–76	Tb927.3.1930	52 847	44.5	PRP17	PRP19
33	1595	1.1E–91	Tb927.9.5880	60 845	44.5	SKIP	PRP19
36	1532	2.9E–86	Tb927.6.4340	12 784	61.1	SSm2-1 (Sm15K)	U2
39	1461	1.3E–68	Tb927.7.6380	23 139	73.7	SSm4	U4
48	1303	9.1E–61	Tb927.3.1780	14 027	59.6	LSm8	U6
50	1249	9.5E–65	Tb927.5.3020	45 934	53.9	SLU7 *
54	1157	3.5E–75	Tb927.8.5180	13 250	46.5	LSm2	U6
55	1135	1.3E–56	Tb927.4.3540	41 174	25.9	Unknown function, conserved
59	1103	6E–51	Tb927.10.11950	22 377	53.6	AD002, CWC15
61	1084	4.1E–56	Tb927.10.10170	48 772	35.6	PRL1	PRP19
63	1060	1E–58	Tb927.2.4540	12 324	81.2	SmB	U1, U4, U5, SL
65	1031	2.9E–53	Tb927.2.5850	12 481	77.6	SmD2	U1, U2, U4, U5, SL
67	982	7.1E–52	Tb927.6.2700	9649	71.8	SmE	U1, U2, U4, U5, SL
69	940	2.9E–43	Tb927.11.14150	24 508	43.5	SPF27	PRP19
73	878	8.4E–40	Tb927.10.4950	14 732	60.5	SSm2.2 (U2-16.5K)	U2
79	809	2.1E–36	Tb927.5.990	21 505	69.1	Unknown function, conserved
85	706	1.1E–42	Tb927.5.2910	19 967	34.2	Unknown function, conserved
86	676	1.6E–30	Tb927.11.13960	14 147	61.4	LSm4	U6
87	662	4.2E–29	Tb927.5.4030	10 207	75.4	LSm7	U6
90	624	1.3E–27	Tb927.3.3480	13 618	47.7	U2-B//	U2
92	607	1.6E–31	Tb927.9.11740	20 280	49.4	PPIL3 *
93	601	2E–26	Tb927.9.10250	8356	88.2	SmF	U1, U2, U4, U5, SL
94	597	7.2E–26	Tb927.8.2090	21 654	44.2	PPIL1	PRP19
95	587	2.2E–29	Tb927.9.3480	20 487	63.9	Cwc21	U5
103	536	2.9E–30	Tb927.7.3120	11 714	45.1	SmD1	U1, U2, U4, U5, SL
136	166	1.2E–4	Tb927.7380	10 116	56.6	LSm3	U6

List of selected PRC5-PTP co-purified proteins, identified by two independent LC/MS/MS analyses and ranked according to their combined, standardized MASCOT protein scores. The list contains the 12 top-ranked hits including non-spliceosomal proteins (cursive), known splicing factors, newly annotated splicing proteins (marked by an asterisk), and conserved proteins of unknown function. Bold lettering indicates PRC subunits. The complete list of proteins is presented in Supplementary Table S2, comprising, in addition, ribosomal proteins, recurrent contaminants of PTP-purified gene expression factors, and annotated proteins unrelated to pre-mRNA splicing. Moreover, seven co-purified coatomer subunits have been omitted although the coatomer has been implicated in spliceosomal snRNP biogenesis previously (54).

¹The lower expect value or higher coverage number between the two analyses are given.